Reservoir sedimentology, characterisation and modelling

The study will focus on stratigraphic architecture, paleogeography and facies trends of Jurassic carbonates along the Moroccan Atlantic Margin, as well as age relationships in the basin.

Part of the work will be outcrop-based, by conducting a regional stratigraphic-sedimentological study. Results will be integrated with subsurface datasets, seismic and well data.

The study will have impact on active oil and gas exploration, in the light of hydrocarbon discoveries in Jurassic carbonates both in Morocco and in the conjugate basins of Canada. Reconnaissance studies of the Jurassic Outcrops north of Agadir have already been conducted.

Students are being interviewed for an early January start. In addition ONHYM are funding one of their staff to undertake an MRes at Manchester as part of this study.

The project commenced in 2006 with a PhD undertaken by Mustafa Karer and supervised by Prof Jonathan Redfern, and was extended to include a field based study led by Dr Stephane Bodin and Prof Jonathan Redfern, with PhD student Jonathan Wood. This latter involved extensive fieldwork in the Murzuk Basin Libya and along the Jeffara Arch (Libya and Tunisa). The research involved collaboration with the LPI Libya and University of Sphax, Tunisia. Aims were to understand the evolving depositional systems, revise the stratigraphy /sequence stratigraphy and characterise /evaluate potential Early Cretaceous reservoirs. The study extended to the subsurface in the Sirt basin, where the "Nubian" sandstones are one of the main reservoir targets. This phase was completed in 2012, with a series of publications and the successful completion of Jonathan Wood's PhD. This project may be extended in future to incorporate further subsurface data, and extend to Egypt and the wider region.

The separate but linked project undertaken by Mustafa Karer (funded by the Libyan government / LPI, with data sponsored by Wintershall) examined the Nubian sandstone and associated igneous activity in the Hameimat Trough, Sirt Basin, Libya. The research utilized high-resolution 3D seismic data, combined with gravity, aeromagnetic, well data and cuttings samples. This project provides valuable insight into seismic imaging of intrusive and extrusive igneous events within the Nubian (Sarir Sandstone) in the Sirt basin, Libya. The presence of volcanics can prove a hazard to drilling, and of emplacement volcanics can have serious detrimental effects on reservoir volume and quality. A number of major oil fields in eastern Sirt basins produce from the Early Cretaceous Nubian sandstone. This significant reservoir is highly structured and has a poorly understood facies distribution. As drilling targets deeper reservoirs or more complex structural areas, developing a better understanding of the Nubian is crucial to successful future exploration. In some localities the Nubian contains significant interbedded volcanics, which have affected and often degraded reservoir quality. The volcanics also affect the seismic response and this makes the exploration program very challenging.

Publications:

Bodin, S., Wood, J., Petitpierre, L., Redfern, J. (2010). " Timing of Early to Mid-Cretaceous tectonic phases along North Africa: New insights from the Jeffara escarpment (Libya-Tunisia)." Journal of African Earth Sciences 58, 3. pp 489-506.

Wood, J.D., S. Bodin, J. Redfern, M.F.H. Thomas, (2014), Controls on facies evolution in low accommodation, continental-scale fluvio-paralic systems (Messak Fm, SW Libya), Sedimentology V 301 p49-69.

PhD Theses:

2009: Mustafa Karer (now with Haliburton Libya): Nubian Sandstones, Hameitmat Trough, Sirte Basin Libya, Evaluating the sedimentology, reservoir characteristics and distribution, and the interbedded igneous units, their origin, distribution and impact on reservoir quality. Libya Gov. Funded

2012 Jonathan Wood (now with Shell International): Sedimentological characterization and regional palaeo-environmental implications of the Messak Fm, SW Libya. NARG Sponsored

The project commenced in 2008 and was led by Dr Sebastian Frohlich (now at Statoil) and Prof Jonathan Redfern, with PhD student Laurent Petitpiere, following an earlier pilot study carried out by Dr Stefan Lubeseder. The project involved extensive fieldwork in Libya on the southern margin of the Ghadames Basin (in part supported by Woodside). Results provide valuable new insights into the depositional environments, and have identified a series of significant incised valleys in the Carboniferous, possible reservoir targets in the subsurface. The work addresses the underlying controls on the system, and refines outcrop to subsurface correlation. In future the project could be extended into the subsurface in Algeria, where these units may offer significant reservoir potential.

Publications:

Fröhlich S., J. Redfern, L. Petitpierre, J. Marshall, M. Power, P. Grech (2009), Diagenesis and reservoir quality evolution of Lower Carboniferous fluvial channels, western Libya) . Journal of Petroleum Geology

Fröhlich, S., Petitpierre, L., Redfern, J., Grech, P., Bodin, S., Lang, S. (2010). "Sedimentological and sequence stratigraphic analysis of Carboniferous deposits in western Libya: recording the sedimentary response of the northern Gondwana margin to climate and sealevel changes." Journal of African Earth Sciences 57 (4), pp. 279-296

Lubeseder S., J. Redfern, L. Petitpierre, S. Fröhlich. (2011). Stratigraphic trapping potential in the Carboniferous of North Africa: developing new play concepts based on integrated outcrop sedimentology and regional sequence stratigraphy (Morocco, Algeria, Libya). Geological Society, London, Petroleum Geology Conference series 2011, v. 7, p. 725-734, doi: 10.1144/?0070725

PhD Thesis:

2012 Laurent Petitpierre (now with Statoil): Sedimentology and Stratigraphy of the Early Carboniferous Marar Formation in Western Libya. NARG sponsored.

Reports: Preliminary Evaluation of the Carboniferous interval: Dr Stefan Lubeseder pilot study

This project undertaken by PhD student Gregg Pyke at Heriot Watt (now at Oxy) was supervised, Dr Andy Gardiner, Prof Patrick Corbett, and also Prof Jonathan Redfern, and examined the Controls on Reservoir Quality within the Cambro-Ordovician Sandstones of the Saharan Platform. Extensive fieldwork was been undertaken in the Murzuk Basin, integrated with a large subsurface dataset, built into a regional Petrel model. Diagenesis of the Memouniat reservoir has been modeled using the Touchstone software ™.

Publications:

No publications have been forthcoming from this work. A number of ppt presentations and extended abstracts are available on the NARG secure server.

PhD Thesis:

This work has still to be submitted for a PhD. A number of ppt presentations and preliminary reports are available to the sponsors.

These projects were run as a lead collaborator in the Atlantic Triassic Project, combining the research power of the Universities of Manchester, Aberdeen and UCD Dublin (Prof Pat Shannon). NARG researchers were Nadine Mader (PhD completed 2008, currently with Maersk) and Ivan Fabuel Perez (PhD completed 2009 currently with Exxon) and Xavier Van lanen (funded by Shell and currently with Statoil). Academic staff from NARG working on this project included Prof Jonathan Redfern, Dr David Hodgetts and Prof Brian Williams. Dr Cat Baudon worked on the project as a PostDoc at Manchester, and the students were also supported by Dr Sophie Leleu from Aberdeen University. This involved an integrated analysis of Late Triassic rift sequences in Canada, Morocco and the North Atlantic (and seismic data from Norway and W Britain). Manchester led the research use of LiDAR and field sedimentology in Morocco, characterising reservoirs in the systems, and also looking at the structural controls using field based analysis in the High Atlas of Morocco, the Argana Basin Morocco and Fundy Basin Canada. A number of publications have come out from this research.

Publications:

Redfern, J., Hodgetts, D. & Fabuel-Perez, I. (2007). Digital analysis brings renaissance for petroleum geology outcrop studies in North Africa. In: First Break 25, pp. 81-87.

Fabuel-Perez, I., Hodgetts, D., & Redfern, J., (2009), A new approach for outcrop characterization and geostatistical analysis of a low-sinuosity fluvial-dominated succession using digital outcrop models; Upper Triassic Oukaimeden Sandstone Formation, central High Atlas, Morocco AAPG Bulletin, 93, 6, pp. 795-827

Fabuel-Perez, I.; Redfern, J.; Hodgetts, D., (2009), Sedimentology of an intra-montane rift- controlled fluvial dominated succession: The Upper Triassic Oukaimeden Sandstone Formation, Central High Atlas, Morocco, Sedimentary Geology, v. 218, iss. 1-4, pp. 103-140.

Baudon, C., Fabuel-Perez, I. and Redfern, J. ( 2009). "Structural style and evolution of a Late Triassic rift basin in the central High Atlas, Morocco; controls on sediment deposition." Geological Journal, 44(6): pp. 677-691.

Van Lanen, X.M.T., Hodgetts, D., Redfern, J., Fabuel-Perez, I. (2009). " Applications of digital outcrop models; two fluvial case studies from the Triassic Wolfville Fm., Canada and Oukaimeden Sandstone Fm., Morocco." Geological Journal, 44(6): 742-760.

Fabuel-Perez, I., Hodgetts, D. and Redfern, J. (2010). " Integration of digital outcrop models (DOMs) and high resolution sedimentology; workflow and implications for geological modelling; Oukaimeden Sandstone Formation, High Atlas (Morocco)." Petroleum Geoscience, 16, 133-154.133-154.

Redfern, J., Shannon, P.M., Williams, B.P.J., Tyrell, S., Leleu, S., Fabuel Perez, I., Baudon, C., Stolfova, K., Hodgetts, D., Speksnijder, A., Haughton, P.D.W, Daly, J.S. , ( 2011) An integrated study of Permo-Triassic basins along the North Atlantic passive margin: implication for future exploration. Geological Society, London, Petroleum Geology Conference series, v. 7, p. 921-936, doi: 10.1144/?0070921

Mader, N. K. and Redfern, J. (2011). A sedimentological model for the continental Upper Triassic Tadrart Ouadou Sandstone Member: recording an interplay of climate and tectonics (Argana Valley; South-west Morocco), Sedimentology, 1365-3091 DOI:10.1111/j.1365-3091.2010.01204.x

Baudon, C., Redfern, J & Van Den Driessche P; J, (2012), Permo-Triassic structural evolution of the Argana Valley and implications on the kinematics and impact of the Atlantic rifting in the High Atlas, Journal of African Earth Sciences, 65, 91-104.

Rarity, F. X. M. T. van Lanen, D. Hodgetts, R. L. Gawthorpe, P. Wilson, I. Fabuel-Perez, and J. Redfern (2013), LiDAR-based digital outcrops for sedimentological analysis: workflows and techniques. Geological Society, London, Special Publications, 387, doi:10.1144/SP387.5

PhD Theses:

2006: Dr Nadine Mader (now working for Maersk): Sedimentology, third order sequence stratigraphy and controlling factors on facies distribution in the Triassic of North Africa. NARG Funded

2009: Dr Ivan Fabuel Perez (now in Exxon): 3D Modelling of Late Triassic Continental mixed fluvial systems; integrating LIDAR with high resolution sedimentology of fluvial facies: High Atlas, Morocco NARG Funded

2011: Dr Xavier Van Lanen (now with Statoil): Quantitative Outcrop Analysis / Integrated Reservoir Modelling of Triassic Fluvial Facies, Minas Basin, Nova Scotia, Canada. Shell International funded.

This project was led by postdoctoral fellow Dr Guy Spence. Outcrop analogues of subsurface naturally fractured carbonate hydrocarbon reservoirs in Egypt were studied to improve our understanding of fracture development and prediction in these complex reservoirs. Field studies were undertaken in Egypt prior to the political situation changing. The project involved the use of DGM/ LiDAR 3-D field mapping of fractured carbonate outcrops, sedimentary logging, sampling and mapping. Data processing and analysis used the Manchester in-house software VRGS and Schlumberger's Petrel software. The aim was to improve understanding of fracture characterisation and property modeling.

Publications:

Spence, G.H., Redfern, J., Aguilera R., Bevan, T., Cosgrove, J.W., Couples, G., Daniel, J-M. (eds) (2014), Advances in the Study of Fractured Reservoirs. Geological Society, London, Special Publication v. 374. and papers therein

The Numidian Flysch is the most widespread tectono-stratigraphic unit in the western Mediterranean. It outcrops in the Alpine nappe belt, in southern Spain, Morocco, Algeria, Tunisia, Sicily and southern Italy. In Sicily and Tunisia it is an Oligocene to mid-Miocene flysch-type deposit sourced from the north-African passive margin and deposited into an east-west trending foreland basin. This study was supervised by Dr Stephane Bodin and Prof Jonathan Redfern, and undertaken as a PhD by Myron Thomas (now Shell). The study focused on outcrops in northern Sicily and Tunisia, evaluating the sedimentology and provenance within the context of the basin as a whole. Special emphasis is placed upon the controls on deposition and provenance of the clastic supply, which until this study were largely unknown. Future work is intended to extend this study to the west into Algerian and Morocco.

Publications:

Thomas, M. F. H., Bodin, S., Redfern, J., Irving, D. H. B. (2010). "A constrained African craton source for the Cenozoic Numidian Flysch: Implications for the palaeogeography of the western Mediterranean basin." Earth Science Reviews 101, 1. pp 1-23.

Thomas, M.F.H., S. Bodin, J. Redfern Comment on European provenance of the Numidian Flysch in northern Tunisia'by Fildes et al.(2010) Terra Nova 22 (6), 501-503

Lubeseder S., J. Redfern, L. Petitpierre, S. Fröhlich. (2011). Stratigraphic trapping potential in the Carboniferous of North Africa: developing new play concepts based on integrated outcrop sedimentology and regional sequence stratigraphy (Morocco, Algeria, Libya). Geological Society, London, Petroleum Geology Conference series 2011, v. 7, p. 725-734, doi: 10.1144/?0070725

PhD Thesis:

2011: Dr Myron Thomas (now with Shell International): Sedimentology of the Nummidian Flysch - NARG Sponsored.

The influence of dolomitisation on Late Cretaceous carbonates in North Africa is often critical to reservoir development. The study has analysed the superbly exposed section along the Jeffara escarpment of southern Tunisia, together with analogue outcrops in Northern Spain.  These outcrops provide an excellent opportunity to study the extensively dolomitised Upper Albian-Lower Turonian shallow water carbonates of the Zebbag Formation (Rhadouane, Kerker and Gattar Members), and similar facies in Spain, which are potential outcrop analogues for reservoirs currently under production and appraisal in North Africa. This study comprised a multi-disciplinary, multi-scale approach using field, petrographical and geochemical data to better constrain the depositional history, diagenetic history and source of diagenetic fluids.

Publications:

3 papers in preparation.

PhD Thesis:

Richard Newport (2014), passed viva and currently undertaking minor correction prior to final submission. The thesis will be available in early 2015.

Mohammed Salem (2^nd year) is funded by the Libyan Government, with data supplied by AGOCO:

The evolution of the Western Sirt Basin in the region of the Dahra Platform, Amin High and Kotla Graben is being evaluated by integrating 2D/ 3D seismic and data from 36 wells. Three tectonic styles can be identified involving regional Pre-rift intra-continental sag, complex multi-stage rifting and modification by wrenching. A major horst-graben system configuration has been delineated, which allows mapping fault distribution and timing throughout the area. Time, interval velocity, isochron, depth, isopach and lithofacies contour maps of the selected (12) horizons have been constructed. These maps are being used to interpret the subsurface architecture of the area from thickness, depth variations and velocity anomalies, in terms of tectonic effect and its control on thickness and facies distribution throughout the Dahra Platform and Kotla Graben area .

Moroccan Atlantic Margin has experienced km-scale vertical movements during its post-rift evolution. Uplifts have controlled the distribution of sedimentary systems and the origin of the sediments delivered to the margin. Untangling the complex post-rift evolution of the NW African margin is fundamental to constraining the behaviour of the shallow-marine to fluvial transition zone as well as the formation and distribution of potential reservoirs

The Lower Cretaceous shallow-marine to fluvial coarse siliciclastic successions of the Agadir Essaouira Basin are an exploration target offshore. However, limited success in recent drilling campaigns reflects the poor understanding of the depositional systems from source to sink. and its links to the eroding hinterland. This highlights the need of a more holistic approach, tracing sediment routing and the main input points through time.

This integrated study aims to develop the first regional paleogeographic and tectonostratigraphic Source-to-Sink model of North-West Africa by deciphering the controls, timing and volume of the sediment supply to the margin and by constraining the importance of sediment recycling, mixing and storage. The main focus is on the late Early Cretaceous marine regression that is associated with substantial input of clastic sediment into the deep-water basins.

The study is currently focusing on source discrimination based on the heavy mineral populations of the potential source areas and on the sampled sandstones in combination with apatite and zircon geochronology.

This study is carried out under the supervision of Stefan Schroeder and Jonathan Redfern (University of Manchester), Shane Tyrrell (NUI Galway) and Giovani Bertotti (TU Delft)